1. Field of the Invention
This invention relates generally to equipment for automatic flash photography, and more particularly, to an indication device in an automatic control type electronic flash unit for indicating whether or not automatic control has taken place when the electronic flash unit has effected discharge light emission. By the term "automatic control" as used in the present specification, I mean that the electronic flash unit senses the reflected light from the subject focused upon and automatically cuts illumination to prevent overexposure.
2. Description of the Prior Art
Automatic control electronic flash units have heretofore been grouped into the serial control type and the parallel control type, and these usually have ready lights. First, in the serial control type electronic flash units, in order to ascertain whether automatic control had taken place, it was necessary to measure the time elapsed from the light emission of the electronic flash unit until the main capacitor thereof was charged to a light emission voltage, that is, until the ready light was turned on. However, such measurement has only been approximate and inaccurate.
Next, in the parallel control type electronic flash units, it was not possible to ascertain whether automatic control had taken place in spite of the presence of the ready light, since charges in the main capacitor were all discharged, even when the electronic flash unit effected no automatic control.
Whether or not an automatic control electronic flash unit has effected automatic control is related to whether or not photography has been properly performed and therefore accurate confirmation of it is desirable.